Parts washing system

ABSTRACT

Provided is a parts washer that includes a multi-tiered basin, a cleaning fluid and a biological component, living within the fluid, that breaks down organic waste. The multi-tiered basin includes a sink member with a false bottom, and a support grid and filter are interposed between the false bottom and a bottom panel of the sink member. The false bottom, support grid, and filter are readily removable from the sink member. The tank is partially filled with the cleaning fluid and a pump and conduit assembly direct a flow of the cleaning fluid to the basin. The cleaning fluid discharged into the basin flows through a drain hole in the false bottom, through the filter and support grid, and then through a drain hole in the bottom panel of the sink member back into the tank for reuse. The cleaning fluid includes, at least, a surfactant that functions to remove organic waste from the parts being washed. The biological component within the cleaning fluid includes nonpathogenic microorganisms that break down the organic waste. The cleaning fluid is not toxic to the microorganisms. The pump and conduit assembly, in addition to aiding in the removal of organic waste, functions to aerate the cleaning fluid to maintain a proper environment for the microorganisms. A heater, thermostat, and level control assembly function to maintain the cleaning fluid within a certain temperature range so as to aid in the removal of organic waste and maintain a proper environment for the microorganisms.

This application is a continuation of application Ser. No. 08/315,902,filed on Sep. 30, 1994, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of cleaning andmore particularly to the field of parts washers.

Parts washers are well known and are often employed in the cleaning ofparts that are contaminated with organic waste products such as, forexample and not limitation, hydrocarbons, oils, and greases. Forbackground and understanding, the type of parts normally being discussedas washed in a parts washer are, for example, automotive parts such asvalves, pistons, transmission parts, covers, and so forth. Mostconventional parts washers include a basin mounted to the top of a tank.The tank is partially filled with a mineral spirits solvent that ispumped from the tank through a conduit that discharges into the basinwhere the parts are washed. The mineral spirits solvent drains from thebasin back to the tank for reuse. A filter is sometimes interposed inthe solvent flowpath to collect organic waste products and particulateswashed from the parts.

While mineral spirits are an effective cleaning solvent, there are manydrawbacks to the employment of parts washers that utilize mineralspirits. For example, some mineral spirit solvents are presentlyclassified by government regulatory agencies as hazardous materialsbecause of their low flash point and potential health concerns. Becauseof this classification, mineral spirits must be used, handled, anddisposed of in compliance with extensive governmental regulations.Further, mineral spirits that are not properly contained can have anegative impact on the environment, and it is not uncommon for workersto have dermatitis and respiratory problems exacerbated by unprotecteduse of mineral spirits. Additionally, many users of mineral spirits findit necessary to dispose of used mineral spirits by having a wastedisposal company pick up the used mineral spirits so that the usedmineral spirits can be disposed of in compliance with the variousgovernmental guidelines and regulations, such disposal can be expensive.

Filters are often incorporated into conventional parts washers to removethe organic waste products and particulates from the solvent. Thus, thefilters eventually become saturated with the organic waste products andparticulates and therefore need to be replaced. The filters are oftendifficult to access and replace. Furthermore, the filters, once theyhave absorbed the organic waste products, are often considered ahazardous material and are therefore difficult to dispose of.

There is, therefore, a need in the industry for a system and methodwhich addresses these and other related, and unrelated, problems.

SUMMARY OF THE INVENTION

Briefly described, the present invention comprises a parts washingsystem characterized by a cooperative interaction among a mechanicalcomponent, fluid component, and biological component. The parts washerapparatus (herein also referred to as the "parts washer") of the partswashing system includes, in the preferred embodiment, a holding tank,cleaning fluid retained within the tank, microorganisms living with thecleaning fluid, a wash basin, a fluid delivery system and an in-linefilter.

In accordance with the preferred embodiment of the present invention,the wash basin is a multi-tiered basin including a sink member defininga bottom panel and a false bottom disposed above the bottom panel. Themulti-tiered basin further includes a support grid and filter interposedbetween the false bottom and the sink member; and the false bottom,support grid, and filter are readily removable from the sink member. Thetank is partially filled with the cleaning fluid and a pump and conduitassembly direct a flow of the cleaning fluid to the basin. The cleaningfluid discharged into the basin flows through a drain hole in the falsebottom, through the filter and support grid, and then through a drainhole defined through the bottom panel of the sink member and cleaningfluid is then returned to the tank for reuse.

In accordance with the preferred embodiment of the present invention,the cleaning fluid includes, at least, a surfactant that functions toremove organic waste from the parts being washed. The biologicalcomponent includes microorganisms that digest the organic waste. Thecleaning fluid is not toxic to the microorganisms such that themicroorganisms survive and reproduce within the cleaning fluidenvironment. The pump and conduit assembly, in addition to aiding in theremoval or organic waste, functions to aerate the cleaning fluid tomaintain a proper environment for the sustainment of the microorganisms.A heater, thermostat, and level control assembly function to maintainthe cleaning fluid within a certain temperature range so as to aid inthe removal of organic waste and maintain a proper environment for thesustainment of the microorganisms. The microorganisms are preferablyintroduced into the cleaning fluid as spores (i.e., in a dormant state).The microorganisms in spore form are preferably adhered to the filterprior to use, and released from the filter when the cleaning fluid flowsthrough the filter.

While the present invention is presented, for the most part, in thecontext of a system, the multi-tiered basin, in isolation, and thecombination of the fluid component and biological component, inisolation, are each considered inventive.

It is therefore an object of the present invention to provide a newmethod, and apparatus for washing parts.

Another object of the present invention is to provide an"environmentally friendly" parts washing system.

Yet another object of the present invention is to decrease theproduction of hazardous waste materials.

Still another object of the present invention is to provide a partswasher that does not require frequent fluid replacement.

Still another object of the present invention is to provide a partswasher that breaks down organic waste into its non-contaminatingcomponents.

Still another object of the present invention is to sustain a biologicalcomponent within a parts washer.

Still another object of the present invention is to provide a partswasher with a multi-tiered sink structure.

Still another object of the present invention is to provide a partswasher with a readily accessible and replaceable filter.

Still another object of the present invention is to greatly reduce (oreliminate) the need for disposal of organic waste washed from parts.

Still another object of the present invention is to wash parts andrecycle resultant organic waste in a closed, self contained environment.

Still another object of the present invention is to provide a cleaningsystem that does not have a toxic effect on users.

Still another object of the present invention is to provide a partswashing system that does not employ a volatile and flammable cleaningfluid; whereby, contrary to that which is required for most, if not all,conventional parts washers, an automatically closing lid is not requiredon the parts washer of the present invention to isolate the cleaningfluid in the case of a shop fire.

Other objects, features and advantages of the present invention willbecome apparent upon reading and understanding this specification, takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exterior perspective view of a parts washer in accordancewith the preferred embodiment of the present invention.

FIG. 2 is a cut-away, perspective, exploded view of isolated componentsof the parts washer of FIG. 1.

FIG. 3 is a front, vertical cross-sectional, cut-away view of the partswasher of FIG. 1, wherein certain portions of the parts washer are notcross-sectioned or cut-away.

FIG. 4 is a perspective, cut-away view of a filter pad portion of theparts washer in accordance with the preferred embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now in greater detail to the drawings, in which like numeralsrepresent like components throughout the several views, FIG. 1 is anexterior, perspective view of a parts washer apparatus (the "partswasher") 10, in accordance with the preferred embodiment of the presentinvention. The parts washer 10 includes a tank 12 and a basin 14. Thebasin 14 includes a sink member 16 that defines a basin cavity 18. Thesink member includes a sink ledge 20 around the periphery of the inletto the basin cavity 18. A back-splash 22 extends upward from a rearportion of the sink ledge 20, and a flexible faucet 24 penetrates therear portion of the sink ledge 20 and terminates in the form of a nozzle26. An optional work light (not shown) extends upward from the basin andilluminates the basin cavity 18. The tank 12 preferably includes a levelindicator 28 and a control panel 30. The level indicator 28 is depictedas comprising a temperature sensitive, liquid crystal display. Thecontrol panel 30 includes an off/on switch 32, a power indicator light34, a low fluid warning light 36, and a timer switch 38.

FIG. 2 is a cut-away, perspective, exploded view of certain components(mentioned below) of the parts washer 10, in accordance with thepreferred embodiment of the present invention. A lower portion of thetank 12 is cut-away, and the faucet 24 and components associated withthe lower portion of the tank 12 are not shown in FIG. 2. The tank 12includes tank walls 42 that define a tank cavity 44 therebetween. Thetank 12 further includes a tank lip 46 that extends around the peripheryof the inlet to the tank cavity 44. The sink member 16 includes sinkwalls 48 extending downward from the sink ledge 20 to a bottom panel 50that defines a drain hole 52 therethrough. The sink walls 48 and bottompanel 50 define the basin cavity 18. The sink walls 48 further define anupper ledge 54 and a lower ledge 56. Each of the ledges 54,56 encirclethe basin cavity 18 and include four segments that together define arectangular shape. Each edge of a planar, rectangular support grid 58rest upon a segment of the lower ledge 56 such that the support grid 58partitions the basin cavity. A rectangular filter pad 60 rests upon andcovers the support grid 58. Each edge of a generally planar, rectangularfalse bottom member 62 rests upon a segment of the upper ledge 54 suchthat the false bottom member 62 also partitions the basin cavity 18 andis disposed above the support grid 58. The false bottom member 62 ispreferably unitary, defines a drain hole 64 therethrough and includes anupwardly protruding lip 66 around the periphery thereof A strainer (notshown) is defined within the drain hole 64. A pair of supplemental drainholes 70 are defined through the rear sink wall 48 just above the filterpad 60.

FIG. 3 is a front, vertical cross-sectional, cut-away view of the partswasher 10, wherein certain portions of the parts washer are, forexplanatory purposes, not cross-sectioned or cut-away. FIG. 3 representseach of the mechanical component (i.e., the hardware, or "parts washer"10, as herein described), the fluid component (represented by a cleaningfluid 72), and the biological component (not seen) living within thecleaning fluid 72. As depicted in FIG. 3, the periphery of the falsebottom member 62 preferably snugly contacts the sink walls 48. The tankcavity 44 is preferably partially filled with a cleaning fluid 72. Asubmersible pump 73 is disposed within the tank cavity 44. When the pump73 is operating, it draws the cleaning fluid 72 from the bottom regionof the tank cavity 44 and discharges the cleaning fluid 72 into aconduit 74. The conduit 74 is connected to and discharges into a base(not shown) of the faucet 24, whereby the fluid discharges from thenozzle 26. The parts washer 10 is preferably further equipped withoptional cleaning accessories (not shown) such as a fountain brush (notshown) that is in fluid communication with the conduit 74. A heater 76,that is controlled by a thermostat 75, selectively heats the cleaningfluid 72, and the heater 76 is acceptably in the form of an electricheating element that extends from the control panel 30 into the depthsof the tank cavity 44. A level probe monitors the depth of the cleaningfluid 72, and the level probe is acceptably in the form of a floatactuated electric switch 78 that includes a magnet equipped float 80. Alip 82 extends around the periphery of the sink ledge 20 forward of theback-splash 22. The lip 82 and back-splash 22 seek to keep cleaningfluid 72 from dripping over the edges of the sink ledge 20. Inaccordance with the presently preferred construction of the presentinvention, much of the parts washer 10 is acceptably constructed fromhigh density polyethylene. In addition, the sink walls 48, bottom panel50, upper ledge 54, lower ledge 56, sink ledge 20, and backsplash 22,are, in accordance with the presently preferred construction, formed asa single, molded, unitary piece.

The biological component is preferably in the form of microorganismsthat biodegrade organic compounds such as, for example and notlimitation, hydrocarbons, oils, greases, petroleum by-products,creolates, polychlorinated biphenols, and other carbon basedcompositions. For example, the microorganisms convert hydrocarboncompounds into elements of water, carbon dioxide, and other digestionproducts. The microorganisms employed preferably not only have thecapability of biodegrading organic waste, but further are resistant toenvironmental shock and have metabolic versatility. Additionally, themicroorganisms are preferably nonpathogenic. Acceptable microorganisms,for example and not limitation, are those from the genera Bacillus,Pseudomonas, and Flavobacterium. Suitable species are well known andreported in the art. The microorganisms preferably range in size fromapproximately three to five microns, whereby they readily pass throughthe filter pad 60. The microorganisms are preferably employed incombination with nitrifying or denitrifing bacteria, phosphatesolubilizing strains of microorganisms, bio-emulsifer producing strainsof microorganisms, and strains of microorganisms which produce growthfactors such as, for example and not limitation, B-vitamins.

The microorganisms are preferably subjected to a preservation techniquein an effort to ensure their viability in the field, their viabilitywhile remaining in spore form for extended periods, and their resistanceto environmental shock. For example, nutrient and buffer components suchas, for example and not limitation, agar, and water soluble adhesivessuch as, for example and not limitation, gum, are preferably mixed withthe microorganisms to promote stability of the microorganisms prior tomixing the microorganisms with a carrier. The carrier is, for exampleand not limitation, acceptably an inert and nutrient organic materialsuch as, but not limited to, heat treated, expanded, cellulose material.The carrier preferably preserves and protects the microorganisms inspore form during storage and transportation. In accordance with thepreferred embodiment of the present invention, an acceptable example ofthe microorganisms is available from the Louisiana Remediation Company,located in Motaire, La., as part number LRC-1.

In accordance with the preferred embodiment of the present invention,the filter pad 60 functions as a vehicle for bringing the microorganismsin spore form into contact with the cleaning fluid 72. The filter pad 60is acceptably constructed, for example and not limitation, from cotton,cellulose, polyolefin fibers, polyester fibers, fiberglass, or the like.Additionally, the filter pad 60 is acceptably constructed fromcombinations of such components. Further, the filter pad 60 isacceptably a ten micron filter or larger. In accordance with thepreferred embodiment of the present invention, microorganisms in sporeform are attached to the filter pad 60 with an adhering agent 84 (FIG.4) that is water soluble and releases the microorganisms when thecleaning fluid 72 is introduced to the filter pad 60, as discussedbelow. Referring to FIG. 4, which is a perspective, cut-away view of thefilter pad 60 in accordance with the preferred embodiment of the presentinvention, the filter pad 60 includes a layer 86 of inert material thatis disposed below a layer 88 of micron-rated media. The inert materialis acceptably fiberglass. The micron-rated media is preferably amaterial that does not have an affinity for hydrocarbons such as, forexample and not limitation, polyester. The microorganisms in spore form,the components mixed therewith as discussed above, and the adheringagent 84 are preferably sandwiched between the layers 86,88 of thefilter pad 60. A portion of the layer 88 is cut-away for explanatorypurposes in FIG. 4 such that the adhering agent 84 is seen. Inaccordance with the preferred embodiment of the present invention, anacceptable adhering agent 84 is "Super 77 Spray Adhesive", which isavailable from the 3M Corporation of St. Paul, Minn. Once themicroorganisms in spore form are attached to the filter pad 60, thefilter pad 60 is acceptably stored until its usage within the partswasher 10 is desired. In accordance with an alternate embodiment of thepresent invention, the microorganisms are added directly to the cleaningfluid 72 without being initially attached to the filter pad 60. Thus,the filter pad 60 functions, in accordance with the preferredembodiment, as both a mechanical filter (i.e., straining particulatematter from the fluid 72) and as an initial transport medium for themicroorganisms: and in an alternate embodiment, the filter pad 60functions solely as a mechanical filter.

In accordance with the preferred embodiment of the present invention,the cleaning fluid 72 is compatible with (i.e., is non-toxic to) themicroorganisms such that the microorganisms are capable of living withinthe cleaning fluid 72. Additionally, the cleaning fluid 72 tends toremove organic waste from parts washed in the basin 14, as will bediscussed in greater detail below. An acceptable cleaning fluid 72, forexample and not limitation, is a mixture of pH neutral emulsifiers andsurfactants containing no volatile organic compounds, phosphates,formaldehyde, biocides, or other toxic materials. The emulsifier andsurfactants are blended in liquid form to produce a biodegradable,non-toxic, non-caustic, non-flammable oil dispersant cleaner anddegreaser. Further, and for example and not limitation, the exemplaryacceptable cleaning fluid 72 contains no known carcinogens, no OSHA(Occupational Health and Safety Act) or DOT (United States Department ofTransportation) regulated chemicals, no ingredients requiring SARA(Superfund Amendments and Reauthorization Act) Title III reporting, noRCRA (Solid Waste Disposal Act as amended by the Resources andConservation Recovery Act of 1976 as amended),hazardous waste chemicals,and no items on the CERCLA (Comprehensive Environmental Response,Compensation and Liability Act) hazardous substance list (based upon therelevant regulations at the time this application was filed).Additionally, and for example and not limitation, the exemplary cleaningfluid 72 is a freely flowing liquid with a specific gravity of 1.083, aslight pleasant odor, no flash point, a boiling point of 210°Fahrenheit, a pH of approximately seven, and which is infinitely solublein water. In accordance with the preferred embodiment of the presentinvention, an acceptable example of the cleaning fluid 72 is availablefrom Warren Chemical Corporation of Robert, La., as part number SeaWash7.

Referring further to FIG. 3, in operation, the pump 73, conduit 74, andfaucet 24 circulate cleaning fluid 72 from the depths of the tank cavity44 to the basin cavity 18 where parts cleaning takes place. The falsebottom member 62 is preferably sufficiently sturdy and well supportedsuch that a variety of parts are capable of being placed thereon forcleaning. In accordance with one method of the present invention,cleaning fluid 72 flows out of the nozzle 26 and the part being washedis oriented within the stream of cleaning fluid 72 exiting the nozzle26. The cleaning fluid 72 removes organic waste from the part beingwashed, and then the cleaning fluid 72, along with the organic waste andany small particulate washed from the part, flows by gravity through thedrain hole 64 and the strainer (not shown) associated therewith. Thestrainer will, of course, keep certain objects from passing through thedrain hole 64. The cleaning fluid 72, organic waste, and remainingparticulate matter then encounter the filter pad 60. Subsequently, thefluid 72 and organic contaminants pass through the support grid 58, anddrain hole 52 to deposit into the tank cavity 44. Should flow throughthe filter pad 60 become obstructed, flow will divert through the pairof supplemental drain holes 70 defined through the rear sink wall 48just above the filter pad 60. The filter pad 60 preferably functions totrap the particulate matter and allow the organic contaminants andcleaning fluid 72 to pass therethrough. Because the filter pad 60 doesnot collect the organic contaminant, it is capable of being disposed ofas a solid waste.

If the filter pad 60 is new or relatively new such that all of themicroorganisms in spore form have not been previously releasedtherefrom, the cleaning fluid 72 releases dormant microorganismsattached to the filter pad 60, and the released microorganisms flow withthe cleaning fluid 72 and organic contaminants through the drain hole 52into the tank cavity 44. Within the tank cavity 44, a large percentageof the microorganisms and organic contaminants will tend to accumulateproximate to the surface of the cleaning fluid 72 such that a largeportion of the biodegradation takes place proximate to the surface ofthe cleaning fluid 72. In theory, this forms a sort of vapor barrierthat tends to minimize the evaporation of the cleaning fluid 72. Ifliving microorganisms are not present in the parts washer 10, increasingamounts of organic waste will accumulate toward the surface of thecleaning fluid 72 in the tank cavity 44, and this condition isindicative of the need to replenish the microorganisms. In theory,however, if the parts washer 10 is used for normal parts cleaning, newmicroorganisms should never need to be added to the cleaning fluid 72 ofthe parts washer 10. Nonetheless, by virtue of the fact that the filterpad 60 is the vehicle for adding the microorganisms to the cleaningfluid 72, as discussed above, microorganisms are added to the cleaningfluid 72 each time a new filter pad 60 is added to the parts washer 10,as discussed in greater detail below. By virtue of the microorganismsdigesting the organic waste within the tank 12, the cleaning fluid 72 is"recycled" within the parts washer 10, whereby the cleaning fluid 72 hasthe potential to last for extended periods of time. It is likely,however, that some cleaning fluid 72 replenishment will be required,however, to make up for evaporative and "drag-out" losses incurred asparts are removed from the basin cavity 18 in wet condition.Furthermore, by virtue of the cooperative effect of the filter pad 60(removing particulate matter) and the microorganisms (digesting organicwaste), the tank is, potentially, seldom in need of "dredging" to removewaste. The pump 73 is preferably proximate to the bottom of the tank 12such that any sludge that might tend to accumulate at the bottom of thetank cavity 44 is circulated through the filter pad 60.

Referring back to FIGS. 1 and 3, when the off/on switch 32 is in the"on" position, electricity is supplied to circuitry (not shown) which ishoused within the control panel 30 by way of a conventional power cord(not shown), and the indicator light 34 is illuminated. In accordancewith the preferred embodiment of the present invention, once the off/onswitch 32 is in the "on" position, the circuitry, in combination withthe thermostat 75, will activate and deactivate the heater 76. While thethermostat 75 senses that the temperature of the cleaning fluid 72within the tank cavity 44 is below a desired temperature, the heater 76is on, and while the thermostat 75 senses that the temperature of thecleaning fluid 72 is at or above the desired temperature, the heater 76is off. The cleaning fluid 72 is preferably maintained in a temperaturerange which supports the lives of the particular microorganisms employedwithin the parts washer 10. In accordance with the preferred embodimentof the present invention, the temperature is acceptably maintained inthe range of approximately 110° to 115° degrees Fahrenheit. The floatactuated electric switch 78 also controls the operation of heater 76.When the magnet equipped float 80 drops downward due to a low level ofcleaning fluid 72, the switch 78 is actuated which, in combination withthe circuitry, disables the heater 76 and causes the low level warninglight 36 to illuminate. Operation of the pump 73 is controlled by thetimer switch 38. A user can manually actuate the timer switch 38 which,in combination with the circuitry, causes the pump 73 to operate andautomatically cut off after a certain period of time. In accordance withan alternate embodiment of the present invention, an additional switch(not shown) is provided that overrides the timer switch 38 such that thepump 73 will remain running as long as the additional switch is "on".

Referring back to FIGS. 2 and 3, the parts washer 10 is designed toprovide easy access to the filter pad 60. Access is obtained by simplylifting the false bottom member 62 out of the basin cavity 18. Inaccordance with the preferred embodiment of the present invention thereis no restrictive engagement between any of the components that aredepicted as exploded away from each other in FIG. 2, whereby thecomponents of the parts washer 10 are readily accessible.

While certain of the preferred and alternate embodiments of the presentinvention have been disclosed herein, other embodiments of the apparatusand methods of the present invention will suggest themselves to personsskilled in the art in view of this disclosure. Therefore, it will beunderstood that variations and modifications can be effected within thespirit and scope of the invention and that the scope of the presentinvention should only be limited by the claims below. Additionally,while it is intended that the scope of the present invention alsoinclude various alternate embodiments, it should be understood that eachof the embodiments disclosed herein, including the preferred embodiment,includes features and characteristics which are considered independentlyinventive. Accordingly, the disclosure of variations and alterationsexpressed in alternate embodiments is intended only to reflect on thebreadth of the scope of the present invention without suggesting thatany of the specific features and characteristics of the preferredembodiment are in any way obvious or unimportant.

We claim:
 1. A system for cleaning hydrocarbons from a part, comprisinga biodegradable, non-toxic, non-caustic, nonflammable oil dispersantcleaner and degreaser fluid, a parts washer including a tank forcontaining the fluid and a basin for receiving the part, a pump andconduit assembly for pumping the fluid from the tank into contact withthe part within the basin, a flowpath defined between the basin and thetank through which the fluid flows from the basin back to the tank, andmicroorganisms within the parts washer for biodegrading thehydrocarbons:the microorganisms substantially sustained within andflowing with the fluid; the parts washer further includes a heater forheating the fluid; and means for controlling said heater to maintain thefluid approximately at a desired temperature and for disabling saidheater as the fluid drops to below a desired level in the tank.
 2. Thecombination of claim 1,wherein the fluid defines a fluid surface in thetank, and wherein substantial portion of the microorganisms live in thefluid proximate to said fluid surface.
 3. The combination of claim 2,wherein a substantial portion of the microorganisms and hydrocarbonsaccumulate proximate to said fluid surface such that a substantialamount of biodegradation takes place proximate to said fluid surface. 4.The combination of claim 1, wherein the heater is at least partiallyimmersed in the fluid.
 5. The combination of claim 1, wherein the heateris constructed and arranged to add heat to the fluid while the fluid isdisposed within the tank.
 6. The combination of claim 1, wherein saidmeans for controlling said heater includes a level sensor cooperatingwith the fluid in the tank and said heater for deactivating said heater.7. The combination of claim 1, wherein said means for controlling saidheater includes a thermostat cooperating with the fluid and said heaterfor activating and deactivating said heater.
 8. The combination of claim7, wherein said means for controlling said heater further includes alevel sensor cooperating with the fluid in the tank and said heater fordeactivating said heater.